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Published on: August 14, 2017
由于闪电减少了的固定,阿基亚生物可能面临危机
R Navarro-González1, C P McKay, D N Mvondo
1Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México Distrito Federal 04510, Mexico. Navarro@nuclecu.unam.mx
Nature
|July 14, 2001
概括
在早期地球上,随着二氧化碳水平的下降,闪电驱动的固定显著减少. 这种减少可能刺激了生物固化的进化,以满足生命的必需营养需求.
科学领域:
- 地质化学 地质化学
- 生物地质化学生物地质化学
- 天体生物学 天体生物学
背景情况:
- 对于生命至关重要,但大气中的N2在很大程度上是不可用的.
- 主要通过闪电的非生物固定,为早期地球提供了.
- 过渡到生物固定的过程尚不清楚.
研究的目的:
- 模拟地球早期的闪电条件并评估固速率.
- 研究大气成分变化对非生物固化的影响.
- 探索生物固化的演变的潜在触发因素.
主要方法:
- 实验模拟雷电在各种Hadean和Archaean大气组成.
- 在不同的CO2和N2度下对氧化产生的分析.
- 在地质时间尺度上的固速率的建模.
主要成果:
- 从闪电中产生的氧化产量减少了两个数量级,因为大气中的二氧化碳在古代期间下降了.
- 无生物供应的这种减少发生在大约22亿年前.
- 2.2 Gyr之后,氧气或甲的上升可能引入了替代的非生物源.
结论:
- 在古代,闪电固定的暂时但显著下降可能已经发生.
- 这种"危机"可能推动了生物固化的发展.
- 了解早期地球的循环是解读生命关键营养素起源的关键.
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